O Cummins NT855 is a 14-liter inline-six diesel engine known for its mechanical fuel system, replaceable wet cylinder liners, and long service history in demanding applications. The platform has been used in mining, marine, power generation, pumping, construction, and other heavy-duty equipment.
Although the NT855 is an established engine family, it is still widely encountered in repair and overhaul work. Understanding the differences between NT855, N855, NTA855, Big Cam, and application-specific versions is important because the same basic 855 architecture has been adapted to very different operating conditions.
What Is the Cummins NT855?
O Cummins NT855 is part of Cummins’ 855-series diesel engine family. It uses an inline six-cylinder configuration with a nominal displacement of 14 liters, or 855 cubic inches.
One of the defining features of the engine is its Cummins PT fuel system. Unlike newer electronically controlled diesel engines, the NT855 relies on a mechanical fuel system in which the fuel pump, injectors, governor, and camshaft work together to control fuel delivery and engine speed. The engine also uses replaceable wet cylinder liners. This design has practical advantages during a major rebuild because worn liners can be replaced without machining the cylinder block in the same way required by many dry-liner engine designs.
Cummins lists the NT855 with naturally aspirated, turbocharged, and turbocharged/aftercooled configurations depending on the specific engine version. This is one reason the name “NT855” alone does not describe every specification found across the 855 family.
Cummins NT855 Specifications
| Especificação | Cummins NT855 |
| Engine family | NT855 |
| Configuration | Inline 6-cylinder |
| Deslocamento | 14 L |
| Deslocamento | 855 in³ |
| Furo | 140 mm |
| Derrame | 152 mm |
| Sistema de combustível | Cummins PT |
| Aspiração | NA, turbocharged or turbocharged/aftercooled, depending on configuration |
| Diesel power range | 280–480 HP on the listed NT855 configuration |
| Typical applications | Mining, industrial, marine, generator and pumping applications |
The 140 mm bore and 152 mm stroke are characteristic dimensions of the 855-series architecture. Specific engine packages can differ in dimensions, accessories, cooling equipment, exhaust arrangement, and weight.
For example, Cummins lists one NT855 configuration at approximately 1,298 × 817 × 1,367 mm with a wet weight of about 1,433 kg. That figure should not be treated as the physical size of every NT855 installation. This distinction matters when comparing Cummins NT855 engine specs with specifications for N855 or NTA855 engines. The displacement may remain essentially the same while the aspiration system, rating, accessories, and application change.
NT855, N855 and NTA855: What’s the Difference?
The names NT855, N855, e NTA855 are closely related, but they do not represent exactly the same configuration. All belong to the Cummins 855-series family and share the basic 14-liter inline-six architecture. The differences are mainly associated with aspiration, aftercooling, ratings, equipment, and application.
NT855
The NT855 designation covers configurations using the 855-series architecture with different aspiration arrangements depending on the specific version. Cummins lists NT855 engines with NA, turbocharged, and turbocharged/aftercooled configurations in its product information.
NTA855
The “A” in NTA855 is associated with aftercooling. NTA855 engines are commonly configured with turbocharging and aftercooling. The aftercooler reduces the temperature of compressed intake air before it enters the engine, increasing air density and supporting the combustion process.
N855
N855 is also used for specific 855-series configurations, particularly in marine and industrial applications. Cummins marine specifications identify N855 engines as 14-liter inline-six diesels with turbocharged and aftercooled aspiration and the PT fuel system.
The important point is that these names identify closely related engines, not one interchangeable parts catalog. A fuel-system component, turbocharger component, gasket, or cooling component should be considered according to the actual engine configuration.
Cummins NT855 Marine Engine
O Cummins NT855 marine engine has been used in both propulsion and auxiliary applications. Marine versions retain the basic 14-liter inline-six architecture but use equipment designed for marine operating conditions. Cummins marine documentation includes NT855-M, N855-M, and NTA855-M configurations.
A marine NT855 installation can include specialized cooling equipment, marine exhaust components, electrical equipment, instrumentation, accessory drives, and pre-lubrication systems.
Published marine ratings also vary by model. For example, Cummins documentation lists NT855-M configurations at several continuous ratings around 240–300 BHP at 1,800 rpm, while NTA855-M versions are available at higher ratings in specific applications. The marine designation is therefore more than a marketing label. The cooling, exhaust, accessory, and installation arrangements can be different from those of an industrial NT855.
Cummins NT855 G6
O Cummins NT855-G6 is a generator-engine configuration designed for fixed-speed power-generation applications.
For the 50 Hz version, the published gross engine output includes:
- Standby: 310 kW / 416 BHP
- Prime: 280 kW / 375 BHP
- Base: 231 kW / 310 BHP
- For the 60 Hz version, Cummins lists:
- Standby: 325 kW / 436 BHP
- Prime: 295 kW / 396 BHP
- Base: 254 kW / 341 BHP
The G6 configuration also illustrates why generator engines need to be considered differently from variable-speed industrial engines. Generator frequency, engine speed, cooling capacity, and rated electrical output are closely connected.
Cummins NT855 Big Cam
The term Cummins NT855 Big Cam refers to a group of later 855-series engine configurations rather than a completely separate engine family.
Big Cam engines are commonly encountered in older heavy-duty equipment and remain relevant in the aftermarket because many of these engines are still maintained or rebuilt. The Big Cam designation matters when working with replacement components because different engine generations can use different fuel-system, valve-train, timing, and accessory components.
Searches such as NT855 Big Cam, NT855 Big Cam Cummins, e Cummins NT855 Big Cam engine are therefore closely related to parts and service information for specific 855-series generations.
Cummins NT855 Parts
O Cummins NT855 parts market covers a wide range of engine systems. These include fuel injection, cylinder-block components, valve-train parts, cooling components, turbocharger-related parts, electrical equipment, accessory drives, and overhaul gaskets.
YIZHI POWER currently carries NT855 products across these major categories.
NT855 Fuel System Parts
Current products include:
- Injetor NT855 3079946
- Injetor NT855 3018834
- NT855 Barrel and Plunger 3047963
- NT855 Barrel and Plunger 3065348
These components are relevant to fuel-system repair and overhaul work on applicable NT855 configurations.
The barrel-and-plunger assembly is particularly important within the PT fuel system because it contributes to the controlled delivery of fuel to the injector system.
NT855 Cylinder Block
The cylinder block is the main structural component of the engine and houses the cylinder liners, crankshaft assembly, and other major components.
YIZHI POWER supplies the Bloco de cilindros NT855 4060393 for engine rebuilding and replacement applications.
The replaceable wet-liner design is one of the more significant features of the NT855 platform. The liners form the cylinder running surface while also transferring heat into the cooling system.
NT855 Cam Follower and Valve Train
The camshaft and valve train control the movement of the engine’s valves and also play an important role in the mechanical fuel system.
YIZHI POWER offers the Rolo seguidor de came NT855 3161423.
Cam-follower wear can affect valve-train movement and the operation of related mechanical components. On a high-hour engine, abnormal valve-train noise or changes in adjustment can justify inspection of the cam and follower system.
NT855 Aftercooler and Oil Cooler
YIZHI POWER currently supplies:
Cummins NT855 3102592 Aftercooler Core
CUMMINS NT855 Oil Cooler 3053393 / 4061462
NT855 Kit, Oil Cooler Seal 3801199
The aftercooler handles compressed intake air on configurations equipped with aftercooling. Lowering intake-air temperature increases air density and supports the engine’s combustion process. The oil cooler controls engine-oil temperature. Oil that operates outside its intended temperature range can affect lubrication performance and component durability.
NT855 Turbocharger Parts
Turbocharging is used on many NT855-family engines, while NTA855 configurations add aftercooling to the air system.
YIZHI POWER supplies the Tubo de drenagem de óleo do turbocompressor NT855 3200178.
The turbocharger depends on proper oil supply and drainage. The drain tube provides the return path for lubricating oil after it passes through the turbocharger.
NT855 Alternator and Accessory Drive
The accessory system provides mechanical power to engine-mounted equipment, while the alternator supports the electrical system.
YIZHI POWER currently supplies:
- Alternador NT855 4061007
- Engrenagem de acionamento do acessório NT855 142689
Cummins NT855 Gasket Sets and Overhaul Parts
- 3801300 NT855 Upper Engine Gasket Set
- 3801300 NT855 Lower Engine Gasket Kit
Upper-engine sealing work can involve components around the cylinder head and other upper sections of the engine, while lower-engine gasket work relates to sealing surfaces in the lower part of the engine assembly.
A rebuild should not be treated as simply replacing every gasket. The condition of the mating surfaces, fasteners, liners, cylinder head, block, and related components determines whether the repair will provide a reliable result.
Cummins NT855 Parts Supplied by YIZHI POWER
| Categoria | NT855 Products |
| Sistema de combustível | Injectors 3079946 / 3018834, Barrel and Plunger 3047963 / 3065348 |
| Cylinder block | Cylinder Block 4060393 |
| Valve train | Cam Follower Roller 3161423 |
| Cooling | Aftercooler Core 3102592, Oil Cooler 3053393 / 4061462 |
| Cooling seals | Oil Cooler Seal Kit 3801199 |
| Turbocharger system | Turbocharger Oil Drain Tube 3200178 |
| Electrical | Alternator 4061007 |
| Accessory drive | Accessory Drive Gear 142689 |
| Gasket sets | Upper Engine Gasket Set 3801300, Lower Engine Gasket Kit 3801300 |
| Complete engine | Conjunto do motor NT855 |
Conclusão
O Cummins NT855 remains an important 855-series diesel platform because of its long service history, mechanical PT fuel system, replaceable wet liners, and broad use across demanding applications. Its specifications are not limited to one
For the aftermarket, that range creates continued demand for Cummins NT855 parts across fuel injection, cylinder blocks, valve train, cooling, turbocharging, electrical systems, accessory drives, and engine gaskets. YIZHI POWER’s current NT855 range covers these major areas as well as complete NT855 engine assemblies, supporting both individual repairs and larger overhaul projects.
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